Estimating the Volume Density from Thin Sections

An approximation formula for the determination of the volume density from thin sections is given. It is applicable under very mild conditions on the structure studied and has a good accuracy.     

Improvement in infected wound healing in type 1 diabetic rat by the synergistic effect of photobiomodulation therapy and conditioned medium

We investigated the effects of photobiomodulation therapy (PBMT) and conditioned medium (CM) of human bone marrow mesenchymal stem cells (hBM-MSC) individually and/or in combination on the stereological parameters and the expression of basic fibroblast growth factor (bFGF), hypoxia-inducible factor (HIF-1α), and stromal cell–derived factor-1α (SDF-1α) in a wound model infected with methicillin-resistant Staphylococcus aureus (MRSA) in diabetic rats. CM was provided by culturing hBM-MSCs. Type 1 diabetes mellitus (T1DM) was induced in 72 rats, divided into four groups, harboring 18 rats each: group 1 served as a control group, group 2 received PBMT, group 3 received CM, and group 4 received CM + PBMT. On days 4, 7, and 15, six animals from each group were euthanized and the skin samples were separated for stereology examination and gene expression analysis by real-time polymerase chain reaction. In the CM + PBMT, CM, and PBMT groups, significant decreases were induced in the number of neutrophils (1460 ± 93, 1854 ± 138, 1719 ± 248) and macrophages (539 ± 69, 804 ± 63, 912 ± 41), and significant increases in the number of fibroblasts (1073 ± 116, 836 ± 75, 912 ± 41) and angiogenesis (15 230 ± 516, 13 318 ± 1116, 14 041 ± 867), compared with those of the control group (2690 ± 371, 1139 ± 145, 566 ± 90, 12 585 ± 1219). Interestingly, the findings of the stereological examination in the CM + PBMT group were statistically more significant than those in the other groups. In the PBMT group, in most cases, the expression of bFGF, HIF-1α, and SDF-1α, on day 4 (27.7 ± 0.14, 28.8 ± 0.52, 27.5 ± 0.54) and day 7 (26.8 ± 1.4, 29.6 ± 1.4, 28.3 ± 1.2) were more significant than those in the control (day 4, 19.3 ± 0.42, 25.5 ± 0.08, 22.6 ± 0.04; day 7, 22.3 ± 0.22, 28.3 ± 0.59, 24.3 ± 0.19) and other treatment groups. The application of PBMT + CM induced anti-inflammatory and angiogenic activities, and hastened wound healing process in a T1 DM model of MRSA infected wound.     

Morphometric Studies of Mitochondria in Tetrahymena pyriformis Exposed to Chloramphenicol or Ethidium Bromide*

Cultures of Tetrahymena pyriformis strain ST were exposed to 300 μg chloramphenicol/ml or 15 μg ethidium bromide/ml for 48 hr. Qualitative assessments of electron micrographs reveal that the abundance of mitochondrial cristae decreases greatly. By equating the spatial characteristics of the organism with those of a prolate spheroid, the distribution and abundance of mitochondria were quantified. Such characterizations reveal that the size of individual mitochondria decreases by 35–60% and that the number of mitochondria/cell increases ～8 fold. The observations are discussed in terms of coordinated mitochondrial and nuclear genetic activities.     

Particle sizes from sectional data

Summary .  We propose a new statistical method for obtaining information about particle size distributions from sectional data without specific assumptions about particle shape. The method utilizes recent advances in local stereology. We show how to estimate separately from sectional data the variance due to the local stereological estimation procedure and the variance due to the variability of particle sizes in the population. Methods for judging the difference between the distribution of estimated particle sizes and the distribution of true particle sizes are also provided.     

A Stereological Approach for Estimation of Cellular Immunogold Labeling and Its Spatial Distribution in Oriented Sections Using the Rotator

Particulate gold labeling applied to ultrathin sections is a powerful approach for locating cellular proteins and lipids on thin sections of cellular structures and compartments. Effective quantitative methods now allow estimation of both density and distribution of gold labeling across aggregate organelles or compartment profiles. However, current methods generally use random sections of cells and tissues, and these do not readily present the information needed for spatial mapping of cellular quantities of gold label. Yet spatial mapping of gold particle labeling becomes important when cells are polarized or show internal organization or spatial shifts in protein/lipid localization. Here we have applied a stereological approach called the rotator to estimate cellular gold label and proportions of labeling over cellular compartments at specific locations related to a chosen cell axis or chosen cellular structures. This method could be used in cell biology for mapping cell components in studies of protein translocation, cell polarity, cell cycle stages, or component cell types in tissues. (J Histochem Cytochem 57:709–719, 2009)     

Cold exposure increases branchial water–blood barrier thickness in the eel

Cold acclimation (5 v . 25° C) of freshwater eel, Anguilla anguilla induces a remodelling of gill fine structure. The increase in branchial water–blood barrier thickness may reflect an adaptive response appropriate for overwintering torpor.     

Is bigger always better? A critical appraisal of the use of volumetric analysis in the study of the hippocampus

A well-developed spatial memory is important for many animals, but appears especially important for scatter-hoarding species. Consequently, the scatter-hoarding system provides an excellent paradigm in which to study the integrative aspects of memory use within an ecological and evolutionary framework. One of the main tenets of this paradigm is that selection for enhanced spatial memory for cache locations should specialize the brain areas involved in memory. One such brain area is the hippocampus (Hp). Many studies have examined this adaptive specialization hypothesis, typically relating spatial memory to Hp volume. However, it is unclear how the volume of the Hp is related to its function for spatial memory. Thus, the goal of this article is to evaluate volume as a main measurement of the degree of morphological and physiological adaptation of the Hp as it relates to memory. We will briefly review the evidence for the specialization of memory in food-hoarding animals and discuss the philosophy behind volume as the main currency. We will then examine the problems associated with this approach, attempting to understand the advantages and limitations of using volume and discuss alternatives that might yield more specific hypotheses. Overall, there is strong evidence that the Hp is involved in the specialization of spatial memory in scatter-hoarding animals. However, volume may be only a coarse proxy for more relevant and subtle changes in the structure of the brain underlying changes in behaviour. To better understand the nature of this brain/memory relationship, we suggest focusing on more specific and relevant features of the Hp, such as the number or size of neurons, variation in connectivity depending on dendritic and axonal arborization and the number of synapses. These should generate more specific hypotheses derived from a solid theoretical background and should provide a better understanding of both neural mechanisms of memory and their evolution.     

A Microcomputer Program for Evaluating Sampling Error: an Application to Stereological Methods for Electron Microscopy

In situations where there is a need to minimize sampling error or sample size, the coefficient of variation (CV) may be used to evaluate sampling error as a function of the number of observations or subjects in a sample. For example, CV is useful for estimating the minimum number of electron micrographs (N_min) required to obtain a representative field sample for stereological analysis. To facilitate the determination of N_min, we have written a program (COEFficient) for DOS microcomputers which calculates CVs. COEF assists the user in reducing error to that which solely reflects biological variability, thereby minimizing the time and cost of subsequent analyses.     

Orbital prefrontal cortex volume predicts social network size: an imaging study of individual differences in humans

The social brain hypothesis, an explanation for the unusually large brains of primates, posits that the size of social group typical of a species is directly related to the volume of its neocortex. To test whether this hypothesis also applies at the within-species level, we applied the Cavalieri method of stereology in conjunction with point counting on magnetic resonance images to determine the volume of prefrontal cortex (PFC) subfields, including dorsal and orbital regions. Path analysis in a sample of 40 healthy adult humans revealed a significant linear relationship between orbital (but not dorsal) PFC volume and the size of subjects' social networks that was mediated by individual intentionality (mentalizing) competences. The results support the social brain hypothesis by indicating a relationship between PFC volume and social network size that applies within species, and, more importantly, indicates that the relationship is mediated by social cognitive skills.